Assuming I had free power for a few months but must keep my rig in a semi restricted area and keep it semi quite what would you recommend doing? The best I could think of was getting a full tower HAF-932 and trying to get 6 5830s going. Semi warm area as airflow via fan can not be provided.

My boss is interested in bitcoin and is 100% willing to donate a few months of power assuming it is not disruptive due to sound. It also has to work in an enclosed space so it can not get to hot. This also will not be running 24/7 so I have to keep hardware costs in mind. I am open to ideas. Thanks.

2) 5830s are noisy and hot. 6 of them will warm up any room, and will not handle an enclosed space well. If you can't vent in cool air / vent out hot air, 6 of just about any cards are too many.

3) Look at eg. 5770/6770 instead - they're relatively low power (100W?) and produce a decent hashrate (~180-200MH/s), pretty close to a 2 MH/w ratio. This doesn't matter as much since your power will be free, but lower power usage = less heat, so efficiency is a real concern here too.

To give some perspective, I ran 4x 5830 and 4x6950 in my basement in a well ventilated room, pulling *cold* air in from outside - even when the outside temps were 35-40F, they heated my entire house, to the point I often had to open more windows.

[edit] Additionally, make sure your boss understands exactly how much power is in question here - a rig with 6x 5830 is going to draw about 1-1.2KW at the wall. Sapping free power for bitcoins probably isn't worth your job

Considering what your boss may be willing to lay down for power costs, perhaps you might want to look at FPGA solutions instead - low heat, low power, but higher upfront costs.

A 'few months' of powering ~180W 5830s could easily pay for a couple of the available solutions floating around the boards that only pull ~10W.

This is kind of a prime example for the argument that 'free power is never free - someone pays for it', since you actually interact with that someone it may be worthwhile to, you know, not suck them dry.

Assuming I had free power for a few months but must keep my rig in a semi restricted area and keep it semi quite what would you recommend doing? The best I could think of was getting a full tower HAF-932 and trying to get 6 5830s going. Semi warm area as airflow via fan can not be provided.

My boss is interested in bitcoin and is 100% willing to donate a few months of power assuming it is not disruptive due to sound. It also has to work in an enclosed space so it can not get to hot. This also will not be running 24/7 so I have to keep hardware costs in mind. I am open to ideas. Thanks.

I really have no idea how these would perform, but I know that SIX 5830's would be disruptive to a quiet office environment.

Rather than lugging around the full tower, these laptops have the AMD 6990M , which would probably due for mining. In addition, the Sager can handle dual 6990Ms.

Should you take this route let us know what kind of numbers you get mining.

Theoretically, you can just plug your laptop in whereever you see an outlet, just keep an eye on it, or it will be gone in a flash.

a laptop like that is going to be just as bad for noise as a high powered desktop, he wants to go with a custom setup regardless of card with watercooling and one or more large radiators with low rpm fans. (small car radiator or heater core even)

Someone should build an "electric heater" that is really just a mining rig in a box with a wireless connection and give it away for free to the elderly and poor. It will work just as efficiently as any other electric heater.

Water cooling won't reduce the thermal load. Water cooling makes the heat transfer more efficient reducing noise and required airflow but energy in = energy out.

If the rig draws 1000W at the wall it will dump 1000W into air.

Why does it need to be in air? My dryer produces 800W of heat, but it all goes outside. It could just as easily be fanned underground as well.

Well given this is an office building I doubt he can drill a hole into the ground or cut a hole in the walls. The rig will be in his office/cubicle so it will be dumping any energy drawn from the outlet right into the immediate area.

My point was the OP should consider this a space heater. Does he want a x watt space heater going 24/7/365 right next to him. Watercooling can make it more efficient and quieter but it can't reduce the amount of wattage it throws off.

I would put this under my desk if I did it but the sounds and heat will be problematic. The only thing I can think of doing is having it water cooled. Never done that or looked into it. I would try to keep everything in a 1 foot by 2.5 foot by 2 foot area.

This office of the Government does not pay for electric either so no one cares. Corruption is one of the expected perks here.

We have aircon on during the day but nothing at night. Anyway at these rates it would take me a while to pay back the hardware I think.

Until the hardware is paid off.. the break-even in your image is 96 days, after that's it's pure profit.

But $400 is going to get you more like 600mh/s.

A pair of 5970s would get you to about 1.4-1.5gh/s, but they're on average $400 each.

I'd budget maybe $250 for the mobo, ram, cpu, and PSU. You're looking at more like $1050 for the system..

Long and short is even with free power it'll be a while before you've paid off the hardware at current difficulty & price, but depending on how long you want to leave it running you could eventually make a profit.